#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2021/10/13 20:24:38 +0900>
"""
Draw block test.

Windows10 x64 21H1 + Python 3.9.7 64bit
"""

import json
import pygame
import sys

SCRW, SCRH = 512, 512
map_w, map_h = 64, 64
tile_w, tile_h = 8, 8
block_w, block_h = 8, 8

imgname = "road_chip.png"
# block_json = "block_road_middle.json"
block_json = "block_road_large.json"


def split_image(img, tilew, tileh):
    """Split image."""
    imgs = []
    w, h = tilew, tileh
    xc = img.get_width() // w
    yc = img.get_height() // h
    for yi in range(yc):
        for xi in range(xc):
            x, y = xi * w, yi * h
            imgs.append(img.subsurface(pygame.Rect(x, y, w, h)))
    return imgs


def put_block(bgmap, blocks, bx, by, id):
    i = 0
    d = blocks[id]
    for y in range(block_h):
        for x in range(block_w):
            bgmap[by + y][bx + x] = d[i]
            i += 1


def create_bg(bgmap, blocks):
    mw = len(bgmap[0])
    id = 0
    x, y = 0, 0
    while id < len(blocks):
        put_block(bgmap, blocks, x, y, id)
        id += 1
        x += block_w
        if x > (mw - block_w):
            x = 0
            y += block_h


def main():
    pygame.init()
    screen = pygame.display.set_mode((SCRW, SCRH), pygame.DOUBLEBUF)

    bgmap = [[0 for i in range(map_w)] for j in range(map_h)]

    # load bg block json
    with open(block_json, 'r') as f:
        block_middle = json.load(f)

    # load bg chip image
    img = pygame.image.load(imgname).convert_alpha()

    # split bg chip image
    imgs = split_image(img, tile_w, tile_h)

    xofs, yofs = 0, 0
    xofs_max = max(0, map_w - (SCRW // tile_w))
    yofs_max = max(0, map_h - (SCRH // tile_h))

    create_bg(bgmap, block_middle)

    running = True

    clock = pygame.time.Clock()

    # Main loop
    while running:

        # update

        # check event
        for ev in pygame.event.get():
            if ev.type == pygame.QUIT:
                running = False
            if ev.type == pygame.KEYDOWN:
                if ev.key == pygame.K_ESCAPE or ev.key == pygame.K_q:
                    # Push ESC or Q key
                    running = False
                if ev.key == pygame.K_SPACE:
                    pass

        # scroll BG
        pygame.event.pump()
        pressed = pygame.key.get_pressed()
        if pressed[pygame.K_LEFT] or pressed[pygame.K_a]:
            xofs -= 1
            if xofs < 0:
                xofs = 0
        if pressed[pygame.K_RIGHT] or pressed[pygame.K_d]:
            xofs += 1
            if xofs > xofs_max:
                xofs = xofs_max
        if pressed[pygame.K_UP] or pressed[pygame.K_w]:
            yofs -= 1
            if yofs < 0:
                yofs = 0
        if pressed[pygame.K_DOWN] or pressed[pygame.K_s]:
            yofs += 1
            if yofs > yofs_max:
                yofs = yofs_max

        # draw start
        screen.fill((40, 60, 200))   # clear screen

        # draw tilemap BG
        xc = SCRW // tile_w
        yc = SCRH // tile_h
        for yi in range(yc):
            for xi in range(xc):
                x = xi + xofs
                y = yi + yofs
                if x >= map_w or y >= map_h:
                    continue
                screen.blit(imgs[bgmap[y][x]], (xi * tile_w, yi * tile_h))

        pygame.display.flip()
        clock.tick_busy_loop(60)

        cap = "Tilemap BG - %5.2f FPS" % (clock.get_fps())
        pygame.display.set_caption(cap)

    pygame.quit()
    sys.exit()


if __name__ == "__main__":
    main()